// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_FORMATS_MP4_TRACK_RUN_ITERATOR_H_
#define MEDIA_FORMATS_MP4_TRACK_RUN_ITERATOR_H_

#include <stddef.h>
#include <stdint.h>

#include <memory>
#include <vector>

#include "base/macros.h"
#include "base/time/time.h"
#include "media/base/media_export.h"
#include "media/base/media_log.h"
#include "media/base/stream_parser_buffer.h"
#include "media/formats/mp4/box_definitions.h"
#include "media/media_features.h"

namespace media {

class DecryptConfig;

namespace mp4 {

    base::TimeDelta MEDIA_EXPORT TimeDeltaFromRational(int64_t numer,
        int64_t denom);
    DecodeTimestamp MEDIA_EXPORT DecodeTimestampFromRational(int64_t numer,
        int64_t denom);

    struct SampleInfo;
    struct TrackRunInfo;

    class MEDIA_EXPORT TrackRunIterator {
    public:
        // Create a new TrackRunIterator. A reference to |moov| will be retained for
        // the lifetime of this object.
        TrackRunIterator(const Movie* moov, const scoped_refptr<MediaLog>& media_log);
        ~TrackRunIterator();

        // Sets up the iterator to handle all the runs from the current fragment.
        bool Init(const MovieFragment& moof);

        // Returns true if the properties of the current run or sample are valid.
        bool IsRunValid() const;
        bool IsSampleValid() const;

        // Advance the properties to refer to the next run or sample. Requires that
        // the current sample be valid.
        void AdvanceRun();
        void AdvanceSample();

        // Returns true if this track run has auxiliary information and has not yet
        // been cached. Only valid if IsRunValid().
        bool AuxInfoNeedsToBeCached();

        // Caches the CENC data from the given buffer. |buf| must be a buffer starting
        // at the offset given by cenc_offset(), with a |size| of at least
        // cenc_size(). Returns true on success, false on error.
        bool CacheAuxInfo(const uint8_t* buf, int size);

        // Returns the maximum buffer location at which no data earlier in the stream
        // will be required in order to read the current or any subsequent sample. You
        // may clear all data up to this offset before reading the current sample
        // safely. Result is in the same units as offset() (for Media Source this is
        // in bytes past the the head of the MOOF box).
        int64_t GetMaxClearOffset();

        // Property of the current run. Only valid if IsRunValid().
        uint32_t track_id() const;
        int64_t aux_info_offset() const;
        int aux_info_size() const;
        bool is_encrypted() const;
        bool is_audio() const;
        // Only one is valid, based on the value of is_audio().
        const AudioSampleEntry& audio_description() const;
        const VideoSampleEntry& video_description() const;

        // Properties of the current sample. Only valid if IsSampleValid().
        int64_t sample_offset() const;
        int sample_size() const;
        DecodeTimestamp dts() const;
        base::TimeDelta cts() const;
        base::TimeDelta duration() const;
        bool is_keyframe() const;

        // Only call when is_encrypted() is true and AuxInfoNeedsToBeCached() is
        // false. Result is owned by caller.
        std::unique_ptr<DecryptConfig> GetDecryptConfig();

    private:
        void ResetRun();
        const TrackEncryption& track_encryption() const;

        uint32_t GetGroupDescriptionIndex(uint32_t sample_index) const;

        // Sample encryption information.
        bool IsSampleEncrypted(size_t sample_index) const;
        uint8_t GetIvSize(size_t sample_index) const;
        const std::vector<uint8_t>& GetKeyId(size_t sample_index) const;
#if BUILDFLAG(ENABLE_CBCS_ENCRYPTION_SCHEME)
        bool ApplyConstantIv(size_t sample_index, SampleEncryptionEntry* entry) const;
#endif

        const Movie* moov_;
        scoped_refptr<MediaLog> media_log_;

        std::vector<TrackRunInfo> runs_;
        std::vector<TrackRunInfo>::const_iterator run_itr_;
        std::vector<SampleInfo>::const_iterator sample_itr_;

        int64_t sample_dts_;
        int64_t sample_offset_;

        DISALLOW_COPY_AND_ASSIGN(TrackRunIterator);
    };

} // namespace mp4
} // namespace media

#endif // MEDIA_FORMATS_MP4_TRACK_RUN_ITERATOR_H_
